/*
 * Copyright [2013-2021], Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.calcite.sql;

import com.google.common.base.Preconditions;
import org.apache.calcite.sql.parser.SqlParserPos;
import org.apache.calcite.sql.type.SqlTypeName;

/**
 * @author chenmo.cm
 * @date 2018/6/17 上午11:08
 */
public class SqlUserDefVar extends SqlLiteral {

    /**
     * Variable name excluding starting "@@", '`' might be included
     */
    private final String name;

    /**
     * Creates a <code>SqlUserDefVar</code>.
     */
    public static SqlUserDefVar create(String name, SqlParserPos pos) {
        return new SqlUserDefVar(name, pos);
    }

    SqlUserDefVar(String name, SqlParserPos pos) {
        super(null, SqlTypeName.USER_SYMBOL, pos);
        this.name = Preconditions.checkNotNull(name);
    }

    public String getName() {
        return name;
    }

    @Override
    public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
        writer.print("@" + name);
    }

    @Override
    public SqlLiteral clone(SqlParserPos pos) {
        return new SqlUserDefVar(name, pos);
    }
}
